I have the same problem with our CB2.
I have changed the battery and followed the service instructions that are referenced, and everything is ok, except that the CB2 cannot boot without a quick fix. Have you fixed anything else in the BIOS besides the address for USB?
No, never.
I performed this procedure probably over 20 times on CB2.0 and 3.0, the only time I had to do the fix on every boot was because of the new battery polarity being wrong.
Is there a pdf that has similar instructions but for a UR5e instead? I am having a similar problem with immediate shutdown during the boot process.
Not that I know of. What year is your controller? I havenāt heard about it happening on the e-series yet, but thatāll be much more expensive to ājustā replace the motherboard.
I did find the e-series BIOS update procedure after all. I thought I had lost it. It is attached here.
NOTE: Messing with the BIOS can leave the robot inoperable. And the guide is fairly old by now, so use it at your own risk.
e-Series BIOS Update guide.pdf (739.8 KB)
After some digging, I have found that my CB2 2013 UR5 48V LED does not light up during startup. The entire machine shuts down 2 seconds later. I measured the terminal for the 48V psu on the masterboard and saw 0V. My next step would be to take apart the CB2 using the service manual and check the psu input and output directly as well as checking the distributor. Is there another possible reason the machine could be acting this way? Could it possibly be the motherboard battery or do my readings narrow the problem to the 48V psu or distributor?
Thank you.
If it shuts off after just 2 seconds, then itās not the 48V supply. 
Then Iām fairly certain itās the motherboard.